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Fencer Intel
high 7.8

CVE-2025-38106 json

io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()

published last yr. modified 3mo ago also EUVD-2025-19837

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()

syzbot reports:

BUG: KASAN: slab-use-after-free in getrusage+0x1109/0x1a60 Read of size 8 at addr ffff88810de2d2c8 by task a.out/304

CPU: 0 UID: 0 PID: 304 Comm: a.out Not tainted 6.16.0-rc1 #1 PREEMPT(voluntary) Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x53/0x70 print_report+0xd0/0x670 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? getrusage+0x1109/0x1a60 kasan_report+0xce/0x100 ? getrusage+0x1109/0x1a60 getrusage+0x1109/0x1a60 ? __pfx_getrusage+0x10/0x10 __io_uring_show_fdinfo+0x9fe/0x1790 ? ksys_read+0xf7/0x1c0 ? do_syscall_64+0xa4/0x260 ? vsnprintf+0x591/0x1100 ? __pfx___io_uring_show_fdinfo+0x10/0x10 ? __pfx_vsnprintf+0x10/0x10 ? mutex_trylock+0xcf/0x130 ? __pfx_mutex_trylock+0x10/0x10 ? __pfx_show_fd_locks+0x10/0x10 ? io_uring_show_fdinfo+0x57/0x80 io_uring_show_fdinfo+0x57/0x80 seq_show+0x38c/0x690 seq_read_iter+0x3f7/0x1180 ? inode_set_ctime_current+0x160/0x4b0 seq_read+0x271/0x3e0 ? __pfx_seq_read+0x10/0x10 ? __pfx__raw_spin_lock+0x10/0x10 ? __mark_inode_dirty+0x402/0x810 ? selinux_file_permission+0x368/0x500 ? file_update_time+0x10f/0x160 vfs_read+0x177/0xa40 ? __pfx___handle_mm_fault+0x10/0x10 ? __pfx_vfs_read+0x10/0x10 ? mutex_lock+0x81/0xe0 ? __pfx_mutex_lock+0x10/0x10 ? fdget_pos+0x24d/0x4b0 ksys_read+0xf7/0x1c0 ? __pfx_ksys_read+0x10/0x10 ? do_user_addr_fault+0x43b/0x9c0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0f74170fc9 Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 8 RSP: 002b:00007fffece049e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000000 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0f74170fc9 RDX: 0000000000001000 RSI: 00007fffece049f0 RDI: 0000000000000004 RBP: 00007fffece05ad0 R08: 0000000000000000 R09: 00007fffece04d90 R10: 0000000000000000 R11: 0000000000000206 R12: 00005651720a1100 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK>

Allocated by task 298: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_slab_alloc+0x6e/0x70 kmem_cache_alloc_node_noprof+0xe8/0x330 copy_process+0x376/0x5e00 create_io_thread+0xab/0xf0 io_sq_offload_create+0x9ed/0xf20 io_uring_setup+0x12b0/0x1cc0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 22: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 __kasan_slab_free+0x37/0x50 kmem_cache_free+0xc4/0x360 rcu_core+0x5ff/0x19f0 handle_softirqs+0x18c/0x530 run_ksoftirqd+0x20/0x30 smpboot_thread_fn+0x287/0x6c0 kthread+0x30d/0x630 ret_from_fork+0xef/0x1a0 ret_from_fork_asm+0x1a/0x30

Last potentially related work creation: kasan_save_stack+0x33/0x60 kasan_record_aux_stack+0x8c/0xa0 __call_rcu_common.constprop.0+0x68/0x940 __schedule+0xff2/0x2930 __cond_resched+0x4c/0x80 mutex_lock+0x5c/0xe0 io_uring_del_tctx_node+0xe1/0x2b0 io_uring_clean_tctx+0xb7/0x160 io_uring_cancel_generic+0x34e/0x760 do_exit+0x240/0x2350 do_group_exit+0xab/0x220 __x64_sys_exit_group+0x39/0x40 x64_sys_call+0x1243/0x1840 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88810de2cb00 which belongs to the cache task_struct of size 3712 The buggy address is located 1992 bytes inside of freed 3712-byte region [ffff88810de2cb00, ffff88810de2d980)

which is caused by the task_struct pointed to by sq->thread being released while it is being used in the function __io_uring_show_fdinfo(). Holding ctx->uring_lock does not prevent ehre relase or exit of sq->thread.

Fix this by assigning and looking up ->thread under RCU, and grabbing a reference to the task_struct. This e ---truncated---

Patch / fix

  • Linux Linux 6.12.34, 6.15.3, 6.16
  • linux Debian 14, Debian 13 6.12.35-1

debian advisories DEBIAN-CVE-2025-38106

  • linux-aws-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-gcp-6.14 Ubuntu 24.04 LTS 6.14.0-1016.17~24.04.1
  • linux-oem-6.14 Ubuntu 24.04 LTS 6.14.0-1012.12
  • linux-riscv-6.14 Ubuntu 24.04 LTS 6.14.0-32.32.1~24.04.1
  • linux-oracle-6.14 Ubuntu 24.04 LTS 6.14.0-1013.13~24.04.1
  • linux-azure-nvidia-6.14 Ubuntu 24.04 LTS 6.14.0-1007.7
  • linux-realtime-6.14 Ubuntu Pro Realtime 24.04 LTS 6.14.0-1012.12~24.04.1

ubuntu advisories UBUNTU-CVE-2025-38106

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.1 6.12.0-124.43.1.el10_1
  • rv RHEL 10.1 6.12.0-124.43.1.el10_1
  • perf RHEL 10.1 6.12.0-124.43.1.el10_1
  • rtla RHEL 10.1 6.12.0-124.43.1.el10_1
  • libperf RHEL 10.1 6.12.0-124.43.1.el10_1
  • kernel-rt RHEL 10.1 6.12.0-124.43.1.el10_1
  • kernel-64k RHEL 10.1 6.12.0-124.43.1.el10_1
  • kernel-core RHEL 10.1 6.12.0-124.43.1.el10_1

red hat advisories RHSA-2026:4012RHSA-2026:3966RHSA-2026:3579RHSA-2026:3088

  • kernel-rt Linux Micro 6.2 6.12.0-160000.6.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2026:20560-1SUSE-SU-2025:21179-1SUSE-SU-2025:03011-1SUSE-SU-2025:02997-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

  • kernel AlmaLinux 9 5.14.0-611.38.1.el9_7
  • rv AlmaLinux 9 5.14.0-611.38.1.el9_7
  • perf AlmaLinux 9 5.14.0-611.38.1.el9_7
  • rtla AlmaLinux 9 5.14.0-611.38.1.el9_7
  • libperf AlmaLinux 9 5.14.0-611.38.1.el9_7
  • kernel-rt AlmaLinux 9 5.14.0-611.38.1.el9_7
  • kernel-64k AlmaLinux 9 5.14.0-611.38.1.el9_7
  • kernel-core AlmaLinux 9 5.14.0-611.38.1.el9_7

almalinux advisories ALSA-2026:3966ALSA-2026:4012

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-38106 updated cvss 4.7

kernel: Linux kernel io_uring: Local privilege escalation, information disclosure, or denial of service via use-after-free

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.6) libperf 5.14.0-570.92.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.92.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.92.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.92.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.92.1.el9_6
    fixed: vendor fix RHSA-2026:3088
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-611.38.1.el9_7, perf 5.14.0-611.38.1.el9_7, rtla 5.14.0-611.38.1.el9_7, python3-perf 5.14.0-611.38.1.el9_7, kernel-devel-matched 5.14.0-611.38.1.el9_7, kernel-64k-devel-matched 5.14.0-611.38.1.el9_7, +7 more
    fixed: vendor fix RHSA-2026:3966
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-124.43.1.el10_1, perf 6.12.0-124.43.1.el10_1, rtla 6.12.0-124.43.1.el10_1, python3-perf 6.12.0-124.43.1.el10_1, kernel-devel-matched 6.12.0-124.43.1.el10_1, kernel-64k-devel-matched 6.12.0-124.43.1.el10_1, +7 more
    fixed: vendor fix RHSA-2026:4012
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.62.1.el10_0, perf 6.12.0-55.62.1.el10_0, rtla 6.12.0-55.62.1.el10_0, python3-perf 6.12.0-55.62.1.el10_0, kernel-devel-matched 6.12.0-55.62.1.el10_0, kernel-64k-devel-matched 6.12.0-55.62.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:3579
  • Red Hat Enterprise Linux AppStream EUS (v.9.6) rv 5.14.0-570.92.1.el9_6, perf 5.14.0-570.92.1.el9_6, rtla 5.14.0-570.92.1.el9_6, python3-perf 5.14.0-570.92.1.el9_6, kernel-devel-matched 5.14.0-570.92.1.el9_6, kernel-64k-devel-matched 5.14.0-570.92.1.el9_6, +7 more
    fixed: vendor fix RHSA-2026:3088
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-611.38.1.el9_7, kernel-64k 5.14.0-611.38.1.el9_7, kernel-core 5.14.0-611.38.1.el9_7, kernel-tools 5.14.0-611.38.1.el9_7, kernel-modules 5.14.0-611.38.1.el9_7, kernel-64k-core 5.14.0-611.38.1.el9_7, +27 more
    fixed: vendor fix RHSA-2026:3966
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-124.43.1.el10_1, kernel-64k 6.12.0-124.43.1.el10_1, kernel-core 6.12.0-124.43.1.el10_1, kernel-tools 6.12.0-124.43.1.el10_1, kernel-modules 6.12.0-124.43.1.el10_1, kernel-64k-core 6.12.0-124.43.1.el10_1, +28 more
    fixed: vendor fix RHSA-2026:4012
show 14 more
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.62.1.el10_0, kernel-64k 6.12.0-55.62.1.el10_0, kernel-core 6.12.0-55.62.1.el10_0, kernel-tools 6.12.0-55.62.1.el10_0, kernel-modules 6.12.0-55.62.1.el10_0, kernel-64k-core 6.12.0-55.62.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:3579
  • Red Hat Enterprise Linux BaseOS EUS (v.9.6) kernel 5.14.0-570.92.1.el9_6, kernel-64k 5.14.0-570.92.1.el9_6, kernel-core 5.14.0-570.92.1.el9_6, kernel-tools 5.14.0-570.92.1.el9_6, kernel-modules 5.14.0-570.92.1.el9_6, kernel-64k-core 5.14.0-570.92.1.el9_6, +27 more
    fixed: vendor fix RHSA-2026:3088
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-611.38.1.el9_7, kernel-debuginfo-common-s390x 5.14.0-611.38.1.el9_7, kernel-debuginfo-common-x86_64 5.14.0-611.38.1.el9_7, kernel-debuginfo-common-aarch64 5.14.0-611.38.1.el9_7, kernel-debuginfo-common-ppc64le 5.14.0-611.38.1.el9_7
    fixed: vendor fix RHSA-2026:3966
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-124.43.1.el10_1, kernel-debuginfo-common-s390x 6.12.0-124.43.1.el10_1, kernel-debuginfo-common-x86_64 6.12.0-124.43.1.el10_1, kernel-debuginfo-common-aarch64 6.12.0-124.43.1.el10_1, kernel-debuginfo-common-ppc64le 6.12.0-124.43.1.el10_1
    fixed: vendor fix RHSA-2026:4012
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.62.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.62.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.62.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.62.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.62.1.el10_0
    fixed: vendor fix RHSA-2026:3579
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-611.38.1.el9_7, kernel-rt-64k 5.14.0-611.38.1.el9_7, kernel-rt-core 5.14.0-611.38.1.el9_7, kernel-rt-modules 5.14.0-611.38.1.el9_7, kernel-rt-64k-core 5.14.0-611.38.1.el9_7, kernel-rt-debug-core 5.14.0-611.38.1.el9_7, +14 more
    fixed: vendor fix RHSA-2026:3966
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-124.43.1.el10_1, kernel-rt-64k 6.12.0-124.43.1.el10_1, kernel-rt-core 6.12.0-124.43.1.el10_1, kernel-rt-modules 6.12.0-124.43.1.el10_1, kernel-rt-64k-core 6.12.0-124.43.1.el10_1, kernel-rt-debug-core 6.12.0-124.43.1.el10_1, +14 more
    fixed: vendor fix RHSA-2026:4012
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.62.1.el10_0, kernel-rt-64k 6.12.0-55.62.1.el10_0, kernel-rt-core 6.12.0-55.62.1.el10_0, kernel-rt-modules 6.12.0-55.62.1.el10_0, kernel-rt-64k-core 6.12.0-55.62.1.el10_0, kernel-rt-debug-core 6.12.0-55.62.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:3579
  • Red Hat Enterprise Linux Real Time EUS (v.9.6) kernel-rt 5.14.0-570.92.1.el9_6, kernel-rt-64k 5.14.0-570.92.1.el9_6, kernel-rt-core 5.14.0-570.92.1.el9_6, kernel-rt-modules 5.14.0-570.92.1.el9_6, kernel-rt-64k-core 5.14.0-570.92.1.el9_6, kernel-rt-debug-core 5.14.0-570.92.1.el9_6, +14 more
    fixed: vendor fix RHSA-2026:3088
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-611.38.1.el9_7, kernel-rt-core 5.14.0-611.38.1.el9_7, kernel-rt-modules 5.14.0-611.38.1.el9_7, kernel-rt-debug-core 5.14.0-611.38.1.el9_7, kernel-rt-modules-core 5.14.0-611.38.1.el9_7, kernel-rt-debug-modules 5.14.0-611.38.1.el9_7, +4 more
    fixed: vendor fix RHSA-2026:3966
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-124.43.1.el10_1, kernel-rt-core 6.12.0-124.43.1.el10_1, kernel-rt-modules 6.12.0-124.43.1.el10_1, kernel-rt-debug-core 6.12.0-124.43.1.el10_1, kernel-rt-modules-core 6.12.0-124.43.1.el10_1, kernel-rt-debug-modules 6.12.0-124.43.1.el10_1, +4 more
    fixed: vendor fix RHSA-2026:4012
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.62.1.el10_0, kernel-rt-kvm 6.12.0-55.62.1.el10_0, kernel-rt-core 6.12.0-55.62.1.el10_0, kernel-rt-modules 6.12.0-55.62.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.62.1.el10_0, kernel-rt-debug-core 6.12.0-55.62.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:3579
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6) kernel-rt 5.14.0-570.92.1.el9_6, kernel-rt-kvm 5.14.0-570.92.1.el9_6, kernel-rt-core 5.14.0-570.92.1.el9_6, kernel-rt-modules 5.14.0-570.92.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.92.1.el9_6, kernel-rt-debug-core 5.14.0-570.92.1.el9_6, +6 more
    fixed: vendor fix RHSA-2026:3088
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
4mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.